He told me that whatever I could achieve would never be good enough for what I was.

The perfection of flattery! Was it that he thought I had not talent of any sort?
It's possible.

He would know.

I've had the idea since that he was jealous.

He wasn't jealous of mankind any more than he was afraid of thieves for his collection; but he may have been jealous of what he could see in me, of some passion that could be aroused.